1. Field of the Invention
The present invention relates to a pattern-forming method.
2. Discussion of the Background
A reduction in dimensions of a resist pattern used for a lithographic process has been desired along with miniaturization of various electronic device (e.g., semiconductor device and liquid crystal device) structures. An ArF excimer laser has typically been used as a short-wavelength light source. A fine resist pattern having a line width of about 90 nm can be formed using ArF excimer laser light. Various resist compositions that can deal with such a short-wavelength light source have been studied. For example, a photoresist composition has been known that includes an acid generator component that generates an acid upon exposure, and a resin component that changes in solubility in a developer due to the acid generated by the acid generator component, and is designed so that a difference in solubility rate occurs between the exposed area and the unexposed area to form a resist pattern on a substrate (see Japanese Patent Application Publication (KOKAI) No. 59-45439).
As a technique that improves the resolution of the photoresist composition using an existing system without increasing the number of steps, a pattern-forming method has been known that utilizes an organic solvent having a polarity lower than that of an alkaline aqueous solution as the developer (see Japanese Patent Application Publication (KOKAI) No. 2000-199953). According to the above pattern-forming method, the optical contrast can be improved by utilizing an organic solvent as the developer instead of an alkaline aqueous solution, and a finer pattern can be formed.